Creating Separate Assignments to User Groups

I am creating a workflow which involves two user groups: A and B

In one of the workflow states I 'Create Separate Assignments.'  Usually I would put individual users here.

Instead of individual users, I would like to 'Create Separate Assignments' for two User Groups.

One person from either of the groups would have to sign off to complete the workflow state.

Is this possible?   

The objective is for one of the users from either Group A and B would have to review and sign off.  I understand this can be done in sequence, but there's no dependency in either of the group's task.  Both groups should have the same amount of time to review.